Just saw the airline's twitter feed. Apparently BI098 (B772ER) was in flight over India from Dubai to Brunei, and warning lights indicating 'AFT Cargo Fire' came up, and pilots requested for the nearest airport for diversion, in this case Mumbai. The flight made a safe landing at 5:30 GMT this morning. No reports of the reg of the aircraft, but a Royal Brunei B777 in Mumbai is definitely a rare sight.
Also interesting to note that they tried to accommodate other passengers on other airlines but not a single seat is available.
At the moment the flight is scheduled to depart Mumbai tomorrow morning. Anyone knows if they're repairing the same aircraft or an additional plane from Brunei is flying in?